In cold climates, it is important to minimize the amount of time needed to warm a vehicle to operating temperature. More specifically, the temperature of the hydraulic oil must be increased to a minimum operating temperature before implement operation, such as a loader, is allowed. In older, fixed-displacement (i.e., constant flow) systems, oil temperatures rose quickly at start-up due to inherent inefficiencies associated with such systems. In contemporary pressure-compensated load-sensing systems, these inefficiencies are reduced to nearly zero when idling. Pressure-compensated load-sensing systems only create hydraulic energy (flow at pressure) when a load signal is present.
Hydraulic oil can be heated by the operator manually by cycling the loader circuit, generating pump flow at high pressure, but this activity can be both fatiguing and time-consuming to the operator.
Accordingly, it would be desirable to provide an automatic process that generated large amounts of pump flow at high pressure, but operating independently of or without resulting in external movement of an implement or requiring continuous input from an operator.